1. Field of the Invention
The present invention relates to head gimbal assemblies (HGAs) and methods for manufacturing the head gimbal assemblies.
2. Description of the Related Art
Head gimbal assemblies are widely used for hard disc drives (HDDs). Such a head gimbal assembly includes a load beam, a metal flexure fixed on the leading end of the load beam, and a slider bonded on an end of the flexure. This slider has a thin film magnetic head element such as a magnetoresistive element (MR element) or a giant magnetoresistive element (GMR element). In this head gimbal assembly, a charged slider may cause electrostatic discharge (ESD), which damages the magnetic head element on the slider. To solve this problem, conductive adhesive resin is conventionally disposed between the flexure and the slider to dissipate the charge of the slider into a suspension. In addition, the breakdown voltage of the slider (the magnetic head element) has further decreased in recent years. Accordingly, a metal film is deposited on the bottom surface (a surface bonded to the suspension) of the slider (metalization) to decrease the contact resistance between the suspension and the slider.
However, these conventional measures are insufficient to prevent the electrostatic discharge; in fact, the electrostatic discharge unfortunately damages the magnetic head element at a constant rate.
In the process of manufacturing the above head gimbal assembly, an oxide film is formed on a surface of the flexure, which is made of a metal spring material (typically, stainless steel). Detailed observations of a head gimbal assembly damaged from the electrostatic discharge revealed that the oxide film prevents the decrease in the contact resistance between the flexure and the slider. This resulted in the present invention.